Hot Relights at High Altitude.
Just happened to try to determine the hot relight ceiling for a Vulcan newly fitted with Bristol Olympus 104 engines circa 1958. Here is an extract from memoirs.
"The performance of the new Mk104 Bristol Olympus engines was remarkable. Acceleration characteristics at altitudes up to and above 50,000 ft were better than any engine in the world at that time. I even found that I could close down an engine, perform a hot relight out to ten seconds after close down and achieve a rapid acceleration to high power from an RPM much lower than normal idle at those altitudes. My report stated that those engines were a credit to the manufacturer."
In those days there was no continuos ignition as installed in some engines now and the concept of relighting an engine whilst still hot was emerging. I do not recall the design of the ignition system and presume that there were a few high energy igniters carefully positioned in the combustion chambers.
My tests for reliabilty of hot relights were limited to within 10 seconds of flame out from closed power lever/throttle and did not extend to a determination of the threshholds where a relight became uncertain.
Were hot relights well known in Vulcan Squadrons?